The invention relates to a tool for fitting a channel-shaped strip into an embracing frictional position on a mount, comprising a tool body, first and second main rollers mounted side-by-side on the body for rotation about respective first and second axes and for receiving the strip in the gap between them and for exerting a force tending to press the side walls of the channel of the strip towards the mount as the rollers rotate and the tool travels along the strip on the mount, the first and second rollers being relatively movable away from and towards each other and the first axis being fixed in relation to the body.
The invention also relates to a method of fitting a channel-shaped strip into a frictionally embracing position on a longitudinally extending mount which has first and second oppositely directed longitudinal faces the first of which is substantially smooth and planar and the second of which has local disruptions which change the thickness of the mount, comprising the steps of fitting the channel of the strip embracingly over the flange, applying sideways-directed forces to the outsides of the side walls of the channel by means of first and second side-by-side rollers carried by a tool body and which contra-rotate about respective first and second axes and through the gap between which the strip passes in contact with the rollers, the first axis being fixed in relation to the tool body and the first roller applying its force to the outside of the side wall of the channel on the first face of the mount.
Such a tool and such a method are shown in GB-A-2 215 762. In the tool there shown, the second roller can be moved towards and away from the first roller by a mechanism which maintains the axes of the two rollers parallel to each other. This requires a relatively complex mechanism, the movement of the second roller away from the first roller being carried out by means of a manually rotated screw or similar arrangement. However, it may be desirable to arrange for the second roller to move away from the first roller automatically, such as in response to variation in thickness of the mount.
Accordingly, the tool as first set forth above is characterised in that the second axis is angularly pivotal, with the second roller, relative to the body about a predetermined pivot axis.
According to the invention, also, the method as first set forth above is characterised in that the second roller is pivotal against a spring bias through a predetermined angular distance relative to the first roller about a predetermined pivot axis whereby to accommodate local variations in thickness along the length of the mount as the tool travels along the strip on the mount while the rollers contra-rotate.